Method and apparatus for vibratory squeeze-forming of metals



Sept. 27, 1966 EVANS' 3,274,812

METHOD AND APPARATUS FOR VIBRATORY SQUEEZE-FORMING OF METALS Filed July1, 1964 2 Sheets-Sheet 1 OSCILLATOR 1 PHASE-SHIFT CIRCUIT OSCILLATORINVENTOR. Sidley 0. Evans AT TORNEY spt. 27, 1966 s o, EVANS 3,274,812

vMETHOD AND APPARATUS FOR VIBRATORY SQUEEZE-FORMING OF METALS Filed July1, 1964 2 Sheets-Sheet 2 FIG. 4

RIGHT -D TRANSDUCER A LEFT TOP TRANSDUCER B D+ BOTTOM TlME (f) FIG.5

TOP

United States Patent METHOD AND APPARATUS FOR VIBRATORY SQUEEZE-FORMHNG0F METALS Sidley 0. Evans, Beaver Falls, Pa., assignor to The Babcock &Wilcox Company, New York, N.Y., a corporation of New Jersey Filed July1, 1964, Ser. No. 379,497

Claims. (CI. 72-60) The present invention generally relates to thesqueezeforming of metals, and more particularly to an improved processand apparatus for applying vibratory energy to a solid state metalmember as it is being squeeze-formed.

The phrase squeeze-forming of metals, used in this specification isintended to cover any of the processes whereby a metal member in asubstantially solid state is forced through a die whereby work isperformed on the member and a reduction in the cross-sectional area ofthe member is effected. Squeeze-forming is thus intended to cover alltypes of hot or cold drawing or extrusion processes, whether the processis carried out with the metal being in its normally hard condition atambient temperature, or whether the metal is in a softened or plasticcondition at elevated temperatures.

Squeeze-forming of metals has attained an important commercial status,and a wide variety of products are now being formed by one or more ofthe several squeezeforming methods which have been developed. It hasbeen found that the application of vibratory energy to the metal beingworked aids significantly in reducing the amount of axial force orpressure required to pass the workpiece through the die and/ or permitsincreasing the speed at which the metal may be passed through the dieupon the application of a given force. Furthermore, the use of vibratoryenergy has been found to be effective in improving the overall qualityof the finished product. U.S. Patent 3,002,614, issued October 3, 1961,in the name of I. B. Jones, shows for instance, the application ofvibratory energy to the various components of a squeeze formingapparatus. In applying the vibratory energy to the apparatus, it hasbeen recognized that the transducers or vibration inducing devices mustbe connected to the part of the apparatus through which the vibrationsare to be transmitted to the workpiece by a force-insensitive support ofthe type shown, for example in U.S. Patent 2,891,180, issued June 16,1959, in the name of W. C. Elmore, in order to effect efficientutilization of the vibratory energy and to concentrate the vibrations inthe area being worked on. It will be understood that this applicationenvisions the use of such a forceinsensitive mount or its equivalent.

It is an object of this invention to provide a method and apparatus forapplying, in a particular manner, vibratory energy to the solid statemetal member being formed in a squeeze-forming process. This inventionis particularly applicable to the squeeze-forming of tubular members,and it is a further object of the present invention to provide a methodof applying vibratory energy to the tubular member being formed in sucha manner so as to improve the concentricity of the member.

To attain these objects, an apparatus for squeeze-forming a solid statemetal member is provided which includes a die having an opening formedtherein, the minimum cross-sectional area of the opening being less thanthe cross-section of the member as defined by its outer originaldimensions. Provisions are also made for axially forcing the metalmember through the die opening, thus performing work on the memberwhereby a reduction in the cross-sectional area of the member iseffected. A plurality of vibrating devices, disposed with respect toeach other preferably in a substantially common plane perpendicular tothe axis of the member, are constructed 3,274,812 Patented Sept. 27,1966 ice and arranged to impart equal amounts of flexural or transversevibratory energy to the member as it passes through the die. Thevibrating devices are maintained uniformly out of time phase withrespect to each other so as to impart a rotating circular vibrationalmovement to the member, thereby causing tangential flow of the workpiecematerial and consequent improvement in workpiece concentricity. Thisresult may m'ost advantageously be obtained by utilizing a pair ofvibrating devices maintained out of time phase with each other andmutually disposed at right angles in a common plane perpendicular to theaxis of the member.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

In the drawings:

FIG. 1 is a schematic diagram of the basic elements of an extrusionpress;

FIG. 2 is a schematic diagram of the essential elements of a drawingapparatus;

FIG. 3 is a diagram showing the application of vibratory energy from twotransducers to .a die according to the present invention;

FIG. 4 is a graphical depiction of the vibration wave forms applied bythe transducers; and

FIG. 5 is an enlarged diagram of the cumulative vibrational movement ofthe workpiece produced by the apparatus shown in FIG. 3 when vibrated inthe cyclic manner shown in FIG. 4.

Referring to FIG. 1, the extrusion press 10 is constructed and arrangedto form a product or tube 1 1B from a metal member or billet 11A. In theoperation of the press 10 the billet 11A is preferably raised to anelevated temperature below its melting .point so that it is in asoftened or plastic condition, and then placed into a chamber formedwithin the cylinder 12. The mandrel 13, which is slidably engaged in anappropriate opening in the ram 16, is then extended through the billet(in the direction indicated by the arrow 15) until its forwardmost endextends through the opening 20A in the die 20 which is rigidly attachedto the forward end of the cylinder 12. The minimum dimensions of theopening 20A thus define the outer shape and size of the tube 11B, andthe outer dimensions of the mandrel 13 define the cross-sectional shapeand size of the longitudinal opening in the tube 11B. Axial force in theforward direction (indicated by the arrow 15) is then exerted on thebillet 11A by the ram 16 to squeeze the metal of the billet 11Aoutwardly through the annular space formed between the opening 20A andthe mandrel 13. During the extrusion process the mandrel 13 and the ram.16 move forward together, thus distributing along the length of themandrel 16 the intense pressures and temperatures which are prevalent atthe die orifice.

It is recognized that various refinements and ramifications have beendeveloped in conjunction with the operation of extrusion presses of thetype shown schematically in FIG. 1, and it is contemplated that thepresent invention may be used in conjunction with any or all of theseimprovements. It should also be recognized that the present inventionmay be utilized in conjunction with an extrusion apparatus producingsolid or non-tubular products, although the benefits of eccentricitycorrection are applicable primarily to tubular products.

Referring to FIG. 2, the drawing mechanism 30 is constructed andarranged to effect a reduction in the cross-section of the incomingmetal member or tube 31A to form the final product or tube 31B. Toaccomplish this, the forward end of the tube 31 is grasped by means ofsuitable jaws 32 and is pulled through the opening 35A in the die 35,the inner dimension of the die defining the outer configuration and sizeof the finished tube 31B. A mandrel 3-3 is held in position within theopening 35A and defines the inner configuration and size of the finishedtube 31B. In the drawing of solid workpieces, the mandrel would, ofcourse, not be used. Here again it is recognized that improvements inthe art have been made to the basic apparatus shown, and it iscontemplated that the present invention may be used in conjunction withany or all of these improvements.

In considering the present invention it should be recognized that it canreadily be used in conjunction with either the extrusion press or thedrawing apparatus as generally discussed above. In the use of vibratoryenergy in such an apparatus, the specific application of vibrations tocertain parts may be physically difficult or practically ineffective.For example, the nature and location of the mandrels 13 and 33 wouldmake their effective vibration extremely difficult. Moreover, theeffectiveness of applying transverse vibratory energy to the ram 16 ofthe extrusion press 10 or the jaw 32 of the drawing apparatus 30 wouldbe minimal because of the constantly changing relative positions ofthese elements and the area in which it is desired to concentrate thevibrations, i.e., primarily the working surface between the die and theworkpiece. It therefore seems obvious that the optimum location for thephysical application of the vibratory energy to the squeeze-formingdevice would be through either the die (20 or 35), or through thecylinder 12 which is rigidly connected to the die 20. Accordingly, thedescription that follows is in terms of introducing vibratory energyinto a tubular workpiece W in a squeeze-forming apparatus through a die,which will hereinafter be generally designated as E; however, the scopeof the invention is intended to encompass the introduction of vibratoryenergy into the workpiece W through any possible physical elements ofthe squeeze-forming apparatus which will effect the desired result.

FIG. 3 shows a die E having physically connected thereto, by suitableforced-insensitive coupling means 38, a pair of vibrating devices ortransducers A and B disposed at right angles to each other andperpendicular to the axes of the die E and the mandrel M. The directionof movement of the tubular workpiece W coincides with the axes of thedie E and the mandrel M, i.e., it is perpendicular to the plane of thepaper on which FIG. 3 is drawn. The transducers A and B may be of anytype suitable for imparting to the die E vibrational energy in the formto be described hereinafter. The transducers A and B are preferably in acommon plane perpendicular to the axis of the die E, or in immediatelyadjacent parallel planes (the transducers A and B are substantially in acommon plane. Generally, the transducers A and B may suitably bepositioned with respect to the die E in any angular relationship bywhich transverse vibrational energy may be imparted to the die E,flexural or transverse vibration being defined for the purposes of thisapplication as any vibration having a component of movement in adirection perpendicular to the direction of movement of the workpiece W.

The excitation coils of the transducers A and B are fed fromrespectively associated oscillators A and 40B which cause thetransducers to produce a vibration having the form of a sine wave asshown graphically in FIG. 4. A phase shift circuit feeds controlvoltages to the oscillators 40A and 40B which are so displaced in phasethat oscillator 40A causes transducer A to vibrate 90 out of time phasewith the vibrations of transducer B caused by oscillator 40B, as can benoted in the comparison of the wave form depictions (for transducers Aand B in FIG. 4. The displacement d of the vibration of transducer A maybe defined as:

d =D cos 21rft and the corresponding displacement for transducer B is:

d =D cos (2r ftp-kg) where D is the maximum displacement or amplitude, fis frequency and t is time.

The calculated values of the displacement of the individual transducersA and B for progressive fractions of t are shown on the followingtabulation:

time (t) Transducer A Transducer 13 E g ill Li u g e A combination ofthese values results in a circulator rotating cumulative vibration ofthe die E and workpiece W, as shown diagrammatically in FIG. 5. Thus, itcan be seen that by using a pair of transducers A and B, disposed atright angles to eac hother and in a substantially common planeperpendicular to the direction of movement of the workpiece W, Where thetransducers have imposed thereon equal sinusoidal vibration wave formswhich are maintained out of time phase with each other, a transverse'vibratory energy is imparted to the workpiece so as to effect acircular rotating vibratory movement of the die E and the workpiece W.

Although the invention has been described in terms of effecting circularvibratory motion, it should be recognized that by altering the waveforms of the vibrations and/or the synchronization of the vibrations,other types of rotating vibrational movement can be effected. Forexample, it would be possible to produce a vibration describing anelliptical or oval path. For the purposes of the specification, the termorbicular is used to describe all of the rotating vibrational movementsencompassed by the present invention, and more particularly to describeall closed paths having a continuously inwardly curving configuration.It should also be recognized that the invention is not intended to belimited to a pair of transducers arranged as described above. Rather itis contemplated that the invention include any plurality of transducersso displaced and operated as to impart an orbicular vibrational movementto the workpiece W in a squeeze-forming apparatus.

While in accordance with the provisions of the statutes there isillustrated and described herein a specific embodiment of the invention,those skilled in the art will understand that changes may be made in theform of the invention covered by the claims, and that certain featuresof the invention may sometimes be used to advantage without acorresponding use of the other features.

What is claimed is:

1. A process for squeeze-forming metals which includes forcing asubstantially solid state metal member through a die opening by applyingaxial pressure to said member to perform work thereon whereby areduction in the cross-section of said member is effected,simultaneously applying transverse vibratory energy to said member froma plurality of vibrating devices which are angularly disposed withrespect to each other, and maintaining said vibrating devices out oftime phase with each other so as to impart an orbicular vibrationalmovement to, said member.

2. A process for squeeze-forming metals which includes forcing asubstantially solid state metal member through a die opening by applyingaxial pressure to said member to perform work thereon whereby areduction in the cross-section of said member is effected,simultaneously applying equal amonuts of transverse vibratory energy tosaid member from a plurailty of vibrating devices Which are angularlydisposed with respect to each other, and maintaining said vibratingdevices uniformly out of time phase with each other so as to impart asubstantially circular vibrational movement to said member.

3. A process for squeeze-forming a substantially solid state metalworkpiece to form therefrom a tubular product, said process comprisingthe steps of axially forcing said workpiece through an annular spaceformed between the innermost boundary of a die opening and a mandrelpositioned therein, simultaneously applying equal amounts of transversevibratory energy to said workpiece from a pair of vibrating deviceswhich are disposed at right angles to each other, and maintaining saidpair of vibrating devices 90 out of time phase with each other so as toimpart a circular vibrational movement to said workpiece, wherebyconcentricity of said tubular product is improved.

4. Apparatus for squeeze-forming a substantially solid state metalmember including a die having an opening formed therein, means foraxially forcing said metal member through said opening to perform workon said member whereby a reduction in the cross-section of said memberis effected, a plurality of vibrating devices constructed and arrangedto impart transverse vibratory energy to said member, said vibratingdevices being angularly disposed with respect to each other, and meansfor maintaining said vibrating devices out of time phase with each otherso as to impart an orbicular rotating vibrational movement to saidmember.

5. Apparatus for squeeze-forming a substantially solid state metalmember including a die having an opening formed therein, means foraxially forcing said metal member through said opening to perform workon said member whereby a reduction in the cross-section of said memberis effected, a plurality of vibrating devices constructed and arrangedto impart transverse vibratory energy to said member through said die,said vibrating devices being angularly disposed with respect to eachother, and means for maintaining said vibrating devices out of timephase with each other so as toimpart a substantially circular rotatingvibrational movement to said member.

6. Apparatus for squeeze-forming a substantially solid state metalmember including a die having an opening formed therein, means foraxially forcing said metal member through said opening to perform workon said member whereby a reduction in the cross-section of said memberis effected, a plurality of vibrating devices constructed and arrangedto impart equal amounts of transverse vibratory energy to said member,said vibrating devices being angularly disposed with respect to eachother in a substantially common plane perpendicular to the axis of saidmember, and means for maintaining said vibrating devices uniformly outof time phase with each other so as to impart a circular rotatingvibrational movement to said member.

7. Apparatus for squeeze-forming a substantially solid state metalmember including a :die having an opening formed therein, means foraxially forcing said metal member through said opening to perform workon said member whereby a reduction in the cross-section of said memheris effected, first and second vibrating devices constructed and arrangedto impart transverse vibratory energy to said member through said die,said first and second vibrating devices being disposed at right anglesto each other, and means for maintaining said first and second vibratingdevices out of time phase with each other so as to impart an orbicularrotating vibrational movement to said member.

8. Apparatus for squeeze-forming a solid state metal member including adie having an opening formed therein, means for axially forcing saidmetal member through said opening to perform work on said member wherebya reduction in the cross-section of said member is effected, the minimumcross-sectional area of said opening being less than the cross-sectionof said member as defined by its outer dimensions, first and secondvibrating devices constructed and arranged to impart equal amounts oftransverse vibratory energy to said member through said die, said firstand second vibrating devices being disposed at right angles to eachother in a common plane perpendicular to the axis of said member, andmeans for maintaining said first and second vibrating devices 90 out oftime phase with each other so as to impart a circular rotatingvibrational movement to said member, the amount of axial force appliedbeing less than the requisite amount of axial force required to passsaid member through said opening in the absence of the applied vibratoryenergy.

9. Apparatus for squeeze-forming a substantially solid state metalworkpiece to produce therefrom a tubular product having a finalcross-sectional area less than the original cross-sectional area of saidworkpiece, said apparatus comprising a die having an opening formedtherein, a mandrel extending into said opening, means for axiallyforcing said workpiece through the space formed between the mandrel andthe innermost boundary of said opening to perform work on saidworkpiece, a plurality of vibrating devices constructed and arranged toimpart equal amounts of transverse vibratory energy to said workpiece,said vibrating devices being angularly disposed with respect to eachother in a substantially common plane perpendicular to the axis of saidworkpiece, and means for maintaining said vibrating devices uniformlyout of time phase with each other so as to impart a circular rotatingvibrational movement to said workpiece, whereby concentricity of saidtubular product is improved.

10. Apparatus for squeeze forming a substantially solid state metalworkpiece to produce therefrom a tubular product having :a finalcross-sectional area less than the original cross-sectional area of saidworkpiece, said apparatus comprising a die having an opening formedtherein, a mandrel extending into said opening, means for axiallyforcing said workpiece through the space formed between the mandrel andthe innermost boundary of said opening to perform work on saidworkpiece, first and second vibrating devices constructed and arrangedto impart equal amounts of transverse vibratory energy to said workpiecethrough said die, said first and second vibrating devices being disposedat right angles to each other in a substantially common planeperpendicular to the axis of said workpiece, and means for maintainingsaid first and second vibrating devices 90 out of time phase with eachother so as to impart a circular rotating vibrational movement to saidworkpiece, whereby concentricity of said tubular products is improved.

References Cited by the Examiner UNITED STATES PATENTS 3,002,614 10/1961 Jones 207-2 FOREIGN PATENTS 955,943 1/ 1957 Germany. CHARLES W.LANHAM, Primary Examiner. E. D. OCONNOR, Assistant Examiner.

1. A PROCESS FOR SQUEEZE-FORMING METALS WHICH INCLUDES FORCING ASUBSTANTIALLY SOLID STATE METAL MEMBER THROUGH A DIE OPENING BY APPLYINGAXIAL PRESSURE TO SAID MEMBER TO PERFORM WORK THEREON WHEREBY AREDUCTION IN THE CROSS-SECTION OF SAID MEMBER IS EFFECTED,SIMULTANEOUSLY APPLYING TRANVERSE VIBRATORY ENERGY TO SAID MEMBER FROM APLURALITY OF VIBRATING DEVICES WHICH ARE ANGULARLY DISPOSED WITH RESPECTTO EACH OTHER, AND MAINTAING SAID VIBRATORY DEVICES OUT OF TIME PHASEWITH EACH OTHER SO AS TO IMPART AN ORBICULAR VIBRATIONAL MOVEMENT TOSAID MEMBER.